Living With Bacteria
A) Prevention of Monerans
- There are many different methods for killing or impeding the growth of bacteria.
i)Sterilization:
-Boiling/Steaming – Autoclave
-Disinfectants/Antiseptics– chemicals which kill bacteria.
Examples: Lysol Bleach Ammonia
Vinegar Alcohol
ii)Temperature :
Freezing/cooling-
-Stops or slows growth and reproduction
Example: Food Preparation, Dead Bodies
Killing with heat - Cooking foods.
iii) Canning/Sealing:
-Removes the atmosphere needed to survive
- Keeps airborne bugs out of food.
iv) Using Preservatives:
- Chemicals that act as a poison to microbes or chemicals that draw water out of microbes.
v) Antibiotics:
-Chemicals produced synthetically or by microorganisms that inhibit the growth of or destroy bacteria, without affecting eukaryotic cells
vi) Bacterial Survival
- Despite all our efforts, bacterial are very opportunistic. When conditions become unfavorable for life (lack of food and water) some bacteria become endospores.
- During endospore formation, a thick internal wall forms to enclose its DNA and part of its cytoplasm. This protects the bacteria and allows it to lie dormant until favorable conditions arise.
B) Protection Against Bacteria
1) First Line of defense: Prevent entry of organisms cutaneous membrane (skin) and mucous membranes.
2) Second Line of defense: Immune system
-Antibodies and Leukocytes (WBC)
-Fever (Rise in body temperature is designed to kill off the invading organisms)
3) Third Line of defense: Chemicals
- Antibiotics
- Vaccines (most are for viruses, but some are designed for bacteria) Ex. Whooping cough vaccine.
C) Resistance in Bacteria
The majority of bacteria reproduce asexually (binary fission), so the only way variation within a population of such bacteria can arise is if bacterial DNA mutates. Some mutations produce bacteria that are resistant to a certain type of antibiotic.
Scenario:
Patient gets bacterial infection and is given an antibiotic. Most bacteria die off, but some are slightly resistant to the antibiotic and they did not receive a high enough dose to wipe them out. These survivors reproduce and cause a second infection. Patient is given a stronger dose or may require a more potent type of antibiotic.
If some mutants continue to live, a new “super bug” arises, one that may require the most potent antibiotic to wipe it out.
At some point we can no longer stop the super bug; as we run out of antibiotics to fight that disease, ex. (flesh-eating disease). This is a very dangerous situation which could lead to an epidemic of bacterial infections that can no longer be treated.
Two factors have led to this problem:
A) Over prescribing antibiotics.
B) Patients not completely finishing their prescription.
D) Uses of Bacteria
i) Food Production:
1. Alcohol 4. Vinegar
2. Cheese 5. Sour cream
3. Cottage cheese 6. Yogurt
ii) Medical Treatment / Genetic Engineering (GE):
1. Vitamin absorption and production.
2. Insulin Production (GE)
3.Growth Hormone Production (GE)
4. Gene Cloning (GE)
iii) Agriculture:
1. Nitrogen fixation àNatural Fertilizers
iv) Waste Disposal: